Enhanced photocatalytic activity of g-C3N4 via modification of NiMoO4 nanorods

Abstract

A novel NiMoO4/g-C3N4 composite with heterojunction structure was prepared via a simple mixing–calcination method and used as a photocatalyst for rhodamine B (RhB) degradation and hydrogen generation under visible light irradiation. Multiple techniques, such as X-ray diffraction (XRD), Fourier transform infrared (FT-IR) spectroscopy, scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray photoelectron spectroscopy (XPS), UV–vis diffuse reflectance spectroscopy (DRS), and photoluminescence (PL) spectroscopy, were applied to investigate the physical and photo properties of the catalysts. Results indicated that the synthesized NiMoO4/g-C3N4 composite can produce hydrogen 4.4 times faster than pure g-C3N4 under visible light irradiation. When the composite was applied in photodegradation of RhB, it was found that the introduction of NiMoO4 nanorods into g-C3N4 can promote the photoabsorption performance and the adsorption of RhB, both of which benefit the photocatalytic reaction. Nevertheless, more important is the formed heterojunction between NiMoO4 and g-C3N4 efficiently retards the recombination of electron-hole pairs, which subsequently significantly promotes the photocatalytic activity. The degradation rate of the optimal NiMoO4/g-C3N4 reaches 0.044min−1, which is 4.0 times that of pure g-C3N4. The proposed mechanism for the enhanced visible-light photocatalytic activity of NiMoO4/g-C3N4 composite is further evidenced by photoluminescence spectroscopy and photocurrent experiments.